High current-carrying capacity switching devices requiring small contact pressures



March 21, 1967 A. BLEIBTREU 3,310,640

HIGH CURRENT-C YING CAPACITY SWITCH DEVICES SMAL L CONTACT PRESSU S F'iled Oct. 4, 1965 REQUIRI lzvrz-wroP Wm M M WWW W.

3,310,640 Patented Mar. 21, 1967 United States Patent ()fiice 3,310,640 HIGH CURRENT-CARRYING CAPACITY SWITCH- ING DEVICES REQUIRING SMALL CONTACT PRESSURES 7 Alexander Bleibtreu, Regensburg,- Germany, assignor to Maschinenfabrik Reinhausen Gebruder Scheubeck KG, Regensburg, Germany Filed Oct. 4, 1965, Scr. No. 492,499 Claims priority, application Germany, Nov. 11, 1964, M 63,075 10 Claims. (Cl. 200-1) This invention relates to switching devices having a high current-carrying capacity and whose contacts do not carry currents when being separated, or brought into engagement, to perform a given switching operation.

It is a general object of this invention to provide improved switching devices of the above description.

It is common practice to provide switching devices intended to have a high current-carrying capacity with a. plurality of pairs of cooperating, i.e. engageable and separable, pairs of contacts of which each pair establishes one of a plurality of parallel current paths.

It is, therefore, another object of this invention to provide improved switching devices having a plurality of pairs ofcontacts establishing a plurality of parallel current paths. e

Switching devices of the aforementioned description are required in regulating transformers having tapped windings to select any desired tap, and switching devices applied to this end are referred to as selector switches. In addition to selector switches, tapped regulating transformers require for a number of other functions switching devicesof the aforementioned description. I

It is, therefore, another object of this invention to provide improved switching devices of the aforementioned description which lend themselves particularly well as selector switches, and for other applications in connection with tapped regulating transformers.

Switching devices of the aforementioned description are also required as disconnects.

It is, therefore, another object-of this invention to provide improved switching devices of the aforementioned description which are applicable as disconnects.

Wherever the current carried by a pair of cooperating contacts exceeds certain limits, it becomes necessary to subdivide each of the pair of contacts into .a plurality of contacts to increase the dissipation of heat from the points of contact engagement. Each cooperating pair of such a plurality of pairs of contacts requires a predetermined contact pressure which is generally established by spring means. Where there is a large number of pairs of contacts connected in parallel, the sum total of the'contact pressure is very high. The lower required for operating the switches, i.e. for simultaneously closing or opening all the pairs of cooperating contacts'thereof, increases in proportion to the sum total of the contact pressure. It is always undesirable to operate switching devices by drives requiring relatively high power, and this is particularly true in regard to switching devices for tap-changing regulating transformers, where space limitations are generally severe and bulky drives intolerable.

It is, therefore, another object of this invention to provide switching devices of the aforementioned description, not subject to these limitations and drawbacks, i.e. wherein the amount of contact pressure which determines the power requirements and bulk requirements of the drive for operating the particular switching device are relatively small.

Theforeg-oing and other general and special object of the invention and advantages thereof will more clearly appear from the ensuing particular description of the invention, as illustrated in the accompanying drawing wherein: a

FIG. 1 is a diagrammatic illustration of a switching device embodying the present invention in the closed contact position of the constituent parts thereof; and

FIG. 2 shows the same structure as FIG. 1 in the open contact position of its constituent parts.

Referring now to the drawings, numerals 11, 12 and 13 have been applied to indicate a plurality of parallel interleaving conductors. Assuming the total current to be carried by the switching device to be J, then each of the three conductors 11, 12, 13 carries J 3. Conductors 11, 12, 13 are spaced by spacers 19 having T-shaped projections 20 forming abutments for pivotable levers 14. Each lever 14 is provided at one end thereof with a fulcrum 15 and on the opposite end with a spherical contact 17 and 18, respectively. The juxtaposed ends of levers 14 carrying contacts 17 and 18 are arranged in interleaving relation. The center of spherical contacts 17, 18 are arranged along a straight line coextensive with a straight line which may be drawn through the points of engagement of superimposed contacts 17 and 18. Contacts 17 and 18 form a column, or string of engaging contacts. Reference numeral 16 has been applied to indicate a rigid bar affixed with the right end thereof to one of the spacers 19 of right conductors 11, 12, 13. The left end of rigid bar 16 supports a spherical contact 17 arranged at the bottom of a column of like spherical contacts which are arranged above it and of which each is supported by a pivotable lever 14. The six superimposed spherical contacts 17, 18 have five points of contact engagement, forming five parallel current paths. Contacts 17 are conductively connected to conductors 11, 12, 13 at the right of the column of contacts 17, 18 and contacts 18 are conductively connected to conductors 11, 12, 13 at the left of the column of contacts 17, 18. This may be achieved by levers 14, or by appropriate shunts (not shown). 7

Helical spring 21 is arranged in coaxial relation to the straight line interconnecting the points of engagement of contacts 17 and 18. The lower end of spring 21 is secured to a pressure-transmitting member 22 having a spherical pressure-transmitting surface engaging the highest contact in the column of contacts 17, 18. Thus the downward pressure of spring 21 establishes the same contact pressure between all constituent contacts of the column of contacts 17, 18. Rigid bar 16 supporting the lowest contact 17 forms a support receiving the thrust of spring 21 transmitted through all the superimposed contacts 17, 18.

Opening of the circuit through contacts 17, 18 involves the operation of means for rendering spring 21 ineffective to cause cessation of the action of spring 21 on contacts 17, 18, i.e. cessation of the pressure of engagement of contacts 17, 18. This may be achieved by any means for raising the upper end of spring 21 indicated in FIG. 2 diagrammaticallyby an arrow pointed in upward direction.

The switching device further includes means for rendering support 16 ineffective to allow pivotal motions of levers 14 and of contacts17, 18 supported by levers 14 about the respective fulcrum 15 of each lever 14.

I In the preferred embodiment of the invention shown, the structure is provided with contact separating means diagrammatically indicated in FIG. 2 bya pair of horizontal arrows, or of arrows at right angles to the axis of helical spring 21. 7 These contact separating means make it possible to jointly move the right conductors 11, 12, 13, the right spacers 19, the right levers 14, the right contacts 17 and bar 16 to the right, and to jointly move left levers 14 and the left contacts 18 to the left. As a result, contacts 17, 18 perform a composite motion, namely the same motion as fulcra 15 of levers 14, plus a pivotal motion of levers 14 about fulcra 15 which may occur under the action of gravity or that of auxiliary spring means (not shown). Due to this composite motion contacts 17, 18 separate, forming a point of break, or a gap, adjacent each point of prior contact engagement.

Closing of the switching device comprises a motion of the right unit 11, 12, 13, 14, 16, 17 from right to left (or opposite to the right arrow of FIG. 2) and a motion of left unit 11, 12, 13, 14, 17 from the left to the right (or opposite to the left arrow of FIG. 2), thus causing engagement of juxtaposed contacts 17 and 18. Thereupon the upper end of spring 21 is lowered, i.e. moved in a direction opposite to that of the vertical arrow of FIG. 1, thus causing engagement of pressuretransmitting member 22 with contact 18 situated on the top of the column of contacts 17, 18. This, in turn, establishes equal pressure between all cooperating or engaging contacts 17, 18.

The force exerted by spring 21 must be equal to the pressure needed between one pair of cooperating contacts, and is unaffected by the number of contacts which are superimposed to form a column of contacts 17, 18. This distinguishes the present structure favorably from prior art structures comprising a plurality of pairs of contacts wherein the total contact pressure, or aggregate contact pressure, is equal to the pressure at one point of contact engagement multiplied by the number of points of contact engagement.

It will be apparent from the foregoing that the left conductors 11, 12, 13 and the right conductors 11, 12, 13 form terminal structures for connecting the switching device into an electric circuit.

Contacts 17 may be referred to as the even numbered or briefly the even contacts, and contacts 18 as the odd numbered, or briefly the odd contacts, of the switching device.

Bar 16 normally precludes a motion of contacts 17, 18 in the direction of the action of spring means 21, i.e. bar 16 is effective as such a motion precluding means as long as the two contact supporting structures to different sides of the vertical line of contact engagement are in the positions thereof shown in FIG. 1.

The brackets B in FIGS. 1 and 2 are intended to indicate that the left hand conductors 11, 12, 13 and the right hand conductors 11, 12, 13 and the intermediate contacts 18, 1718, 17 are provided to establish three electrically parallel current paths. The current paths established by conductors 11, 12, 13 are also parallel in a geometrical sense.

The two spacers 19 at the right of FIGS. 1 and 2 are a first conductor integrating means integrating right conductors 11, 12, 13 into a first structural assembly unit, i.e. a unit whose constituent parts are jointly movable, as indicated by the arrow at the right of FIG. 2. In a like fashion the two spacers 19 at the left integrate left conductors 11, 12, 13 into a second assembly unit.

Reference numeral 22a has been applied to indicate an abutment defining the position of the upper end of spring 21. tion longitudinally of the column of contacts 18, 17--18, 17 abutment 22a is a means for selectively rendering spring 21 effective and ineffective as a contact-pressureestablishing means. Bar 16 and the lowest spherical contact 17 are an abutment means which normally receives the force exerted by spring 21 and transmitted to bar 16 and lowest contact 17 by the intermediary of the column of contacts 18, 17.

It will be understood that I have illustrated and described herein a preferred embodiment of my invention and that various alternations may be made in the details thereof without departing from the spirit and the scope of the invention as defined by the appended claims.

Since abutment 22a is movable in a direc- V I claim as my invention.

1. A switching device including:

(a) a plurality of superimposed physically engaging contacts forming a straight column of contacts including even contacts and odd contacts;

(b) a first plurality of parallel conductors, each of said first plurality of conductors being conductively connected to and supporting adjacent one end thereof one of said even contacts;

(0) a second plurality of parallel conductors, each of said second plurality of conductors being conductively connected to and supporting adjacent one end thereof one of said odd contacts, each of said second plurality of conductors being displaced relative to each of said first plurality of conductors in a direction longitudinally of said column of contacts;

(d) pivot means for said even contacts and pivot means for said odd contacts to allow relative movement of said even contacts and of said odd contacts in a direction substantially longitudinally of said column of contacts;

(e) a pair of conductor integrating means including a first conductor integrating means integrating said first plurality of conductors into a first structural assembly unit and a second conductor integrating means integrating said second plurality of conductors into a second structural assembly unit, said first assembly unit and said second assembly unit being movable relative to each other in a direction substantially transversally of said column of contacts;

(f) a common contact-pressure-establishing spring means arranged adjacent one of the ends of said column of contacts normally establishing contact pressure between all of the constituent contacts of said column of contacts, said spring means having a line of action coextensive with said straight line;

(g) means for rendering said spring means substantially ineffective to reduce said contact pressure normally established by said spring means between the constituent contacts of said column of contacts; and

(h) abutment means arranged adjacent the other end of said column of contacts remote from said spring means to normally receive the force exerted by said common spring means transmitted through said plurality of contacts to said abutment means, said abutment means being integral and jointly movable with one of said pair of conductor integrating means.

2. A switching device as specified in claim 1 wherein said abutment means includes the lowest contact of said column of contacts.

3. A switching device including:

(a) a plurality of substantially spherical superimposed engaging contacts forming a column of contacts including even contacts and odd contacts, the points of engagement of said plurality of contacts defining a straight line;

(b) a first plurality of parallel conductors arranged substantially at right angles to said straight line and each being conductively connected adjacent one end thereof to one and supporting said one of said plurality of even contacts;

(c) a second plurality of parallel conductors arranged substantially at right ahgles to said straight line and each being conductively connected adjacent one end thereof to one and supporting said one of said plurality of odd contacts, each of said second plurality of conductors being displaced relative to each of said first plurality of conductors in a direction longitudinally of said straight line;

(d) pivot means for said even contacts interposed in said first plurality of conductors and pivot means for said odd contacts interposed in said second plurality of conductors to allow pivotal movement of said even contacts and of said odd contacts about said pivot means thereof;

(e) a pair of structural units including a first structural unit and a second structural unit, said first structural unit including a first plurality of spacers between the constituent conductors of said first plurality of conductors structurally integrating said'first plurality of conductors for joint movement thereof, said second structural unit including a second plurality of spacers arranged between the constituent conductors of said second plurality of conductors for joint movement thereof, said first structural unit and said second structural unit being movable relative to each other in a direction transversally of said straight line;

(f) a common contact-pressure-establishing helical spring having an axis coextensive with said straight line, said spring being arranged adjacent oneof the ends of said column of contacts normally establishing contact pressure in the direction of said straight line between all of the constituent contacts of said column of contacts, said spring having one end arranged adjacent one of the ends of said column of contacts and said spring having another end remote from said one of the ends of said column of con-r tacts; a

(g) a first abutment normally supporting said end of said spring remote from said one of the ends of said column of contacts and being movable in a direction substantially longitudinally of said column of contacts away from said column of contacts to render said spring substantially ineffective as contact pressure establishing means; and

(h) a second abutment arranged adjacent the other of the ends of said column of contacts to normally support the constituent contacts thereof and to receive the force exerted by said spring transmitted through said plurality of contacts to said second abutment, said second abutment being integral with and jointly movable with one of said pair of structural units.

4. A switching device as specified in claim 3 wherein said second abutment includes the lowest contact of said column of contacts, and wherein said lowest contact of said column of contacts is supported by a rigid bar which is in turn supported by one of said pair of structural units.

5. A switching device including (a) a plurality of relatively movable contacts aligned along a straight line and forming a string of contacts, said plurality of contacts including even contacts and odd contacts;

(b) parallel conductor means arranged in staggered relation and having juxtaposed ends, said conductor means including even conductorsrand odd conductors and supporting said plurality of contacts at said juxtaposed ends thereof, said even conductors supporting said even contacts and said odd conductors supporting said odd contacts;

(c) spring means acting upon one of said plurality of contacts situated at one of the ends of said string of contacts and exerting contact pressure upon the points of engagement of all of said plurality of contacts;

(d) suporting means for one of said plurality of contacts at the other of the ends of said string of contacts for normally precluding relative motion of said plurality of contacts under the action of said spring means; and

(e) contact separating means movable substantially at right angles to the direction of action of said spring means for establishing gaps between all of said plurality of contacts, said contact separating means supporting said supporting means to render said supporting means ineifective upon movement of said contact separating means at right angles to the direction of action of said spring means.

6. A switching device including (a) a plurality of pivotable levers having juxtaposed interleaving ends forming a column of cooperating contacts including even contacts and odd contacts;

(b) a common contact-pressure-establishing spring acting upon one of said plurality of contacts situated on one of the ends of said column in a direction substantially longitudinally thereof and imparting equal contact pressures to all of said plurality of contacts;

(c) supporting means for one of said plurality of contacts at the other of the ends of said column for normally precluding a pivotal motion of said plurality of levers under the action of said spring means; and

(d) contact separating means for separating said interleaving ends of said plurality of levers to allow pivotal motions of said plurality of levers to establish gaps between all of said plurality of contacts, said supporting means for said one of said plurality of contacts at the other end of said column being under the control of, and jointly movable with, said contact separating means.

7. A switching device including (a) a plurality of substantially parallel levers having juxtaposed interleaving ends;

(b) guide means for said plurality of levers for guiding said interleaving ends thereof along circular paths of relatively limited length;

(c) a plurality of spherical contacts each supported by one of said plurality of levers at the interleaving ends thereof, said plurality of contacts having normally points of contact engagement situated in a straight line;

(d) common spring means acting upon said plurality of contacts substantially in a direction of said straight line to cause engagement of said plurality of contacts under pressure;

(e) a support for one of said plurality of contacts receiving the thrust exerted by said spring means;

(f) means for rendering said spring means inefiective to cause cessation of said pressure of engagement of said plurality of contacts;

(g) means for rendering said support ineffective to allow movement of said plurality of levers and of said plurality of contacts along said circular paths of relatively limited length, and

(h) movable means for establishing a spacing between alternate of said plurality of contacts and said straight line in -a direction substantially transversally of said straight line.

8. A switching device including (a) a plurality of parallel interleaving conductors;

(b) spacer means filling the gap between said plurality of conductors;

(c) a plurality of pivotable levers having juxtaposed interleaving ends;

(d) abutment means integral with said spacer means for limiting the pivotal motion of said plurality o levers;

(e) a plurality of engaging contacts having points of engagement situated substantially along a straight line, said plurality of contacts being supported by said plurality of levers at the interleaving ends thereof and each of said plurality of contacts being conductively connected to one of said plurality of conductors;

I (f) common spring means acting upon all of said plurality of contacts in the direction of said substantially straight line to cause engagement thereof under pressure;

(g) a support for receiving the thrust of said spring means;

(h) means for rendering said spring means ineifective to cause cessation of said pressure of engagement of said plurality of contacts; 7

(i) means for rendering said support ineflective to allow pivotal motions of said plurality of levers and of said plurality of contacts, and

(j) movable means for establishing a spacing between alternate of said plurality of contacts and said straight line in a direction substantially transversally of said straight line.

9. A switching device including (a) a plurality of interleaving parallel conductors;

(b) spacer means filling the gaps between said plurality of conductors;

(c) a plurality of pivotable levers having juxtaposed interleaving ends;

(d) each of said plurality of spacer means having a substantially T-shaped projection integral therewith and forming a pair of abutments limiting the pivotal motion of said plurality of levers;

(e) a plurality of engaging spherical contacts having points of engagement situated substantially along a straight line, said plurality of contacts being supported by said plurality of levers at the interleaving ends thereof, and each of said plurality of contacts being conductively connected to one of said plurality of conductors;

(f) common spring means acting substantially along said straight line upon all of said plurality of contacts to cause engagement thereof under pressure;

(g) a support for receiving the thrust of said spring means;

(h) means for rendering said spring means ineffective to cause cessation of said pressure of engagement of said plurality of contacts; and

(i) contact operating means movable in a direction substantially at right angles to said straight line for separating said plurality of contacts and establishing gaps between said plurality of contacts.

10. A switching device as specified in claim 9 wherein said support for receiving the thrust of said spring means is in the form of a rigid bar supported on one end thereof by one of said spacer means and supporting on the other end thereof a contact engaged by one of said plurality of contacts.

References Cited by the Examiner UNITED STATES PATENTS 2,894,095 7/1959 VVijkman 200l X ROBERT K. SCHAEFER, Primary Examiner.

J. R. SCOTT, Assistant Examiner. 

1. A SWITCHING DEVICE INCLUDING: (A) A PLURALITY OF SUPERIMPOSED PHYSICALLY ENGAGING CONTACTS FORMING A STRAIGHT COLUMN OF CONTACTS INCLUDING EVEN CONTACTS AND ODD CONTACTS; (B) A FIRST PLURALITY OF PARALLEL CONDUCTORS, EACH OF SAID FIRST PLURALITY OF CONDUCTORS BEING CONDUCTIVELY CONNECTED TO AND SUPPORTING ADJACENT ONE END THEREOF ONE OF SAID EVEN CONTACTS; (C) A SECOND PLURALITY OF PARALLEL CONDUCTORS, EACH OF SAID SECOND PLURALITY OF CONDUCTORS BEING CONDUCTIVELY CONNECTED TO AND SUPPORTING ADJACENT ONE END THEREOF ONE OF SAID ODD CONTACTS, EACH OF SAID SECOND PLURALITY OF CONDUCTORS BEING DISPLACED RELATIVE TO EACH OF SAID FIRST PLURALITY OF CONDUCTORS IN A DIRECTION LONGITUDINALLY OF SAID COLUMN OF CONTACTS; (D) PIVOT MEANS FOR SAID EVEN CONTACTS AND PIVOT MEANS FOR SAID ODD CONTACTS TO ALLOW RELATIVE MOVEMENT OF SAID EVEN CONTACTS AND OF SAID ODD CONTACTS IN A DIRECTION SUBSTANTIALLY LONGITUDINALLY OF SAID COLUMN OF CONTACTS; (E) A PAIR OF CONDUCTOR INTEGRATING MEANS INCLUDING A FIRST CONDUCTOR INTEGRATING MEANS INTEGRATING SAID FIRST PLURALITY OF CONDUCTORS INTO A FIRST STRUCTURAL ASSEMBLY UNIT AND A SECOND CONDUCTOR INTEGRATING MEANS INTEGRATING SAID SECOND PLURALITY OF CONDUCTORS INTO A SECOND STRUCTURAL ASSEMBLY UNIT, SAID FIRST ASSEMBLY UNIT AND SAID SECOND ASSEMBLY UNIT BEING MOVABLE RELATIVE TO EACH OTHER IN A DIRECTION SUBSTANTIALLY TRANSVERSALLY OF SAID COLUMN OF CONTACTS; (F) A COMMON CONTACT-PRESSURE-ESTABLISHING SPRING MEANS ARRANGED ADJACENT ONE OF THE ENDS OF SAID COLUMN OF CONTACTS NORMALLY ESTABLISHING CONTACT PRESSURE BETWEEN ALL OF THE CONSTITUENT CONTACTS OF SAID COLUMN OF CONTACTS, SAID SPRING MEANS HAVING A LINE OF ACTION COEXTENSIVE WITH SAID STRAIGHT LINE; (G) MEANS FOR RENDERING SAID SPRING MEANS SUBSTANTIALLY INEFFECTIVE TO REDUCE SAID CONTACT PRESSURE NORMALLY ESTABLISHED BY SAID SPRING MEANS BETWEEN THE CONSTITUENT CONTACTS OF SAID COLUMN OF CONTACTS; AND (H) ABUTMENT MEANS ARRANGED ADJACENT THE OTHER END OF SAID COLUMN OF CONTACTS REMOTE FROM SAID SPRING MEANS TO NORMALLY RECEIVE THE FORCE EXERTED BY SAID COMMON SPRING MEANS TRANSMITTED THROUGH SAID PLURALITY OF CONTACTS TO SAID ABUTMENT MEANS, SAID ABUTMENT MEANS BEING INTEGRAL AND JOINTLY MOVABLE WITH ONE OF SAID PAIR OF CONDUCTOR INTEGRATING MEANS. 